Reflector antenna for microwaves



June 10, 1958; REINHARD El'AL 2,838,756

REFLECTOR ANTENNA FOR MICROWAVES Filed Sept. 10, 1956 United States Patent REFLECTOR ANTENNA FOR MICROWAVES Louis Reinhard, Lucerne, and Hans Klauser, Zurich, Switzerland, assignors to Alhiswerk Ziirich A. G., Zurich, Switzerland, a Swiss corporation Application September 10, 1956, Serial No. 608,741

Claims priority, application Switzerland October 18, 1955 9 Claims. (Cl. 343--912) Our invention relates to a reflector screen antenna for microwaves whose reflector is composed of flat metal rods which are located at uniform mutual spacing in respective planes parallel to one another and parallel to the reflector axis, and which are joined with transverse tie strips and have their ends atached to a frame. Antenna screen structures of this type are known in the microwave technique.

Heretofore such reflector antennas have been made either by casting or by welding them together from individual parts. However, for wave lengths below approximately cm. the cross sections of the reflector rods can be given the required mechanical strength at such a small size that the reflector can no longer be produced by casting. On the other hand, with welded reflectors the required tolerance of about M16 relative to the shape of the reflector surface, this tolerance being determined by the electric operating requirements, can be maintained only for wave lengths above aproximately 10 cm. For smaller wave lengths, therefore, a construction is chosen in which the antenna is composed of preshaped individual parts by applying a joining method, such as the use of rivets, which practically does not modify the ultimate shape 'of the individual parts, particularly of the reflector rods. Such manufacture, however, is diflicult because the rods, particularly in reflectors of double curvature have different angular position relative to the transverse tie strips or frame at respectively different junction points.

It is an object of our invention to simplify the manufacture of microwave reflector antennas generally of the above-mentioned screen type and to make them suitable for any wave length including those below 10 cm.

To this end and in accordance with a feature of our invention the reflector metal rods are joined with the transverse tie strips and with the antenna frame by means of linkage pieces each having two pivots axes perpendicular to each other, and by bracing adjacent reflector rods against each other by means of spacers.

The foregoing and more specific features of our invention will be explained more in detail with reference to the embodiment illustrated by way of example, on the drawing. In the drawing:

Fig. 1 is a front view of the reflector antenna.

Fig. 2 is a longitudinal section along the line II-II in Fi 1. v

ifig. 3 is a cross-section along the line IIIIII in Fig. 1.

Fig. 4 is a partial cross section along the in Fig. l on a larger scale, and

Fig. 5 is a partial longitudinal section along the line V--V in Fig. 1 shown on a larger scale.

The illustrated reflector antenna is provided with a rotationally symmetrical parabolic reflector composed of a multiplicity of flat metal rods 1. All metal rods 1 are uniformly spaced from each other a distance dependent upon the operating wave length and are locatedin planes which are parallel to one another and parallel to the re- 2,838,756 Patented June 10, 1958 flector axis. The rods 1 are firmly interconnected by means of struts or tie strips 2 extending transverse to the rods 1, and the respective ends of each metal rod 1 are firmly joined with a frame 3 of circular shape. The means for mounting the reflector antenna on a standard or other support are not illustrated on the drawing.

The particular connection of the metal rods 1 with the strips 2 and the frame 3 is apparent from Figs. 4 and 5, Fig. 5 showing only one of the metal rods. The metal rods 1 are joined with the strips 2 on the one hand and with the frame 3 on the other hand by respective linkages in form of flat metal pieces 4 and 5. Each of these link pieces is provided with eyes at the respective ends, and the axes of the two eyes are turned relative to each other. The frame 3 and the strips 2 have U-shaped channel cross section. Pivot pins 6 and 7 are mounted in and between the two limbs of the U-profile of each of the parts 2, 3 and extend transverse to the longitudinal direction of these parts. Journaled upon each pivot pin is one of the linkage pieces 4 or 5 by means of the above: mentioned eye which is rolled into the end of the linkage piece.

In the illustrated example, the metal rods 1 are also given a U-shaped cross section as is aparent, for instance, at 1a in Fig. 4. The ends of the link pieces 4 and 5 are located between, and in face-to-face engagement with, the limbs of the U-profile and are connected therewith by means of transverse bolts 8 pasing through the entire U-profile structure. All flat link pieces 4 for connecting the metal rods with the strips 2 have identical shape and size; and all flat link pieces 5 for connecting the metal rods 1' with the frame 3 are likewise of identical design. However, the construction may also be modified so that all link pieces have the same shape and size. The connecting elements for securing the strips 2 to the frame 3 consist of U-shaped angle pieces 9 (Fig. 4) to which the parts 2 and 3 are fixed by means of rivets.

The metal rods are braced against each other by means of spacers 10. The spacers 10 are located on one side of the metal rods 1 and are secured thereto together with the link pieces 4. On the opposite side, each spacer 10 loosely abuts against the adjacent metal rod 1. For damping disturbing mechanical oscillations of the metal rods 1, as may be caused by rhythmic movements of the reflector antenna or by Wind forces, the spacers 10 are preferably designed as tubular bodies into which a plug 11 of elastic material, for instance rubber, is inserted so as to protrude from the end of the tubular spacer.

The manufacture of a reflector antenna according to the invention, as exemplified by the embodiment described above, is relatively easy and economical. The metal rods 1 and the tie strips 2 have one and the same shape respectively due to the fact that the axial spacing of these parts at all junction points is the same because of the uniform length of the link pieces 4. Both parts therefore can be brought into the desired shape with the aid of a single bending jig or gauge. Drilling jigs are readily applicable for drilling the rows of holes and holding the respective parts during drilling operation in the predetermined accurate shape. The linkage pieces are preferably produced by stamping. The individual parts prefabricated in this manner are then riveted together with the aid of suitable tools, thus definitely securing and rigidly bracing the metal rods in their proper origi nal shape.

In this manner, reflector antennas for wave lengths below 10 cm., for instance 3 cm. and less, can be built with reflector dimensions in the order of 1 m. Even if profiled light-metal structures are used for the individual parts of the antenna, as is favorable in certain cases for instance for rapidly movable antennas, a satisfactory rigidity and stability of shape of the reflector is readily secured.

We claim:

1. Reflector antenna for microwaves, comprising a reflector frame, a multiplicity of flat metal rods uniformly spaced from each other in respective pianos parallel to one another and parallel to the reflector axis, tie strips extending transversely to said rods, .each of said rods forming respective junctions with said frame and with said strips, a link piece located at-eachof said respective junctions and forming two pivots at its two ends respectively, said two pivots having mutually perpendicular pivot axes and connecting said link piece with one of said rods and with one of said frame and tie strips respectively.

2. A reflector antenna according to claim 1, wherein all said link pieces that connect said rods with said frame are of identical design, and allsaid link pieces that connect said rods with said tie strips are of identical design.

3. In a reflector antenna according to claim 1, said link pieces consisting of flat and elongated parts each having at its respective ends two eye portions forming said pivots.

4. In a reflector antenna according to claim 1, said frame and said strip having each a U-shaped cross section, pivot pins mounted across the limbs of said .U- shaped cross section, each of said link pieces having a curved end which forms an eye, and said eye being pivotally seated upon one of said pivot pins.

5. In a reflector antenna according to claim 1, said rods having a U-shaped cross section, said link pieces having an end portion located flat between the limbs of said U-shaped cross section of one of said rods and having a hole also located between said limbs to form one of said pivots, and a pivot pin mounted on said limbs and traversing said hole for pivotally joining said link piece with said rod.

6. A reflector antenna according to claim 1, compris 4 ing spacers all projecting from said respective rods in the same direction, each of said spacers being secured to one of said rods together with one of said respective link pieces and being in loose abutting engagement with the next adjacent rod.

7. A reflector antenna according to claim 1, comprising spacers all projecting from said respective rods in the same direction, each of said spacers being secured to one of said rods together with one of said respective link pieces and being in loose abutting engagement with the next adjacent rod, each of said spacers comprising damping means for suppressing disturbing vibration of said rods.

8. A reflector antena according to claim 1, compris ing tubular spacers each being mounted on one of said 'espcctive rods in coaxial relation to one of the pivot axes of one of said link pieces and fastened to said rod together with said link piece, each of said spacers projecting from said rod toward an adjacent rod, and a plug of elastic material inserted into said tubular spacer and protruding therefrom into engagement with said adjacent rod.

9. Reflector antenna for microwaves, comprising a reflector frame, a multiplicity of fiat metal rods uniformly spaced from each other in respective planes parallel to one another and parallel to the reflector axis, tie strips extending transversely to said rods, each of said rods forming respective junctions with said frame and with said strips, a flat and elongated link piece located at each of said respective junctions and having two pivot eyes at its two ends respectively, said pivot eyes having mutually perpendicular axes, pivot pins articulately joining said link piece with one of said rods and with one of said respective frame and strips, said frame and rods as well as said strips and link pieces consisting of light metal.

.No references cited. 

